C. elegans has been selected as a "high connectivity" animal model for cellular development. This very small, simple animal has been widely adopted for experimental study due to extensive genetic resources and accessible cell biology. The complete genome of the worm is being sequenced by the Worm Genome Consortium. Much of the animal's adult anatomy has been reconstructed from electron micrographs of serial thin sections. However, EM techniques are not widely utilized by the C. elegans community, and most data from previous EM studies are not easily accessed. The C. elegans Anatomy Center will concentrate on extending these EM methods in C. elegans, particularly to study cellular changes during normal development and in mutant animals, and to conduct EM-immunocytochemical studies to localize antigens at the ultrastructural level. Such studies will be conducted in close collaboration with NIH- and NSF-funded laboratories, as a directed component of their ongoing research efforts. In addition, the Center will publish much more detailed information regarding the anatomy of the nematode in the form of annotated electron micrographs. This information will be supplied on CD-ROMs, over the World Wide Web, and possibly in book form. Where necessary, the Center will conduct additional EM surveys of the wild type anatomy at several developmental stages to supplement the Atlas, particularly to fill gaps in general knowledge. This pre-resource application will build the capabilities of the Center over an initial three year period. The applicants intend to request a P40 or P41 grant later for continued support of the Center.